EXTERNAL PRESSURE-VOLUME MONITOR FOR ENDOTRACHEAL CUFF

EXTERNAL PRESSURE-VOLUME MONITOR FOR ENDOTRACHEAL CUFF James O. Elam A monitoring system is comprised of an elastomer balloon housed in a spherical perforated cage which is designed to continuously indicate the state of collapse or expansion of the internal cuff or cuffs of an endotracheal tube. This balloon monitor is interconnected in series with the pneumatic channel through which the cuff or cuffs are inflated. The volume of said monitoring balloon may be observed visually with reference to its filling the cage enclosure denoting thereby its state of inflation and therefore, also that of the endotracheal cuff. Calibration of the balloon monitor provides means of accurately observing both the volume and pressure of air in the system. Therefore, visual inspection of the monitor indicates by reason of said calibration the prevailing level of pressure in the patient's endotracheal-tube cuff. Since the maintenance of safe cuff pressures results in a normal position of the balloon, in contact with the cage, electrical and electronic means may be arranged appropriately between the balloon and inner surface of the cage to produce a warning signal in the event of cuff overdistension and an alarm signal in the event of cuff collapse.